/*
 * [New BSD License]
 * Copyright (c) 2011-2012, Brackit Project Team <info@brackit.org>  
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Brackit Project Team nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.brackit.xquery.util.aggregator;

import java.util.Arrays;

import org.brackit.xquery.QueryException;
import org.brackit.xquery.sequence.NestedSequence;
import org.brackit.xquery.xdm.Sequence;

/**
 * Aggregator for sequence concatenation
 * 
 * @author Sebastian Baechle
 * 
 */
public class SequenceAggregator implements Aggregator {
	private Sequence[] buf = new Sequence[5];
	private int len;

	@Override
	public void add(Sequence s) throws QueryException {
		if (s == null) {
			return;
		}
		if (len == buf.length) {
			buf = Arrays.copyOf(buf, ((buf.length * 3) / 2 + 1));
		}
		buf[len++] = s;
	}

	@Override
	public Sequence getAggregate() {
		if (len == 0) {
			return null;
		}
		if (len == 1) {
			return buf[0];
		}
		if (buf.length != len) {
			buf = Arrays.copyOf(buf, len);
		}
		return new NestedSequence(buf);
	}

	@Override
	public void clear() {
		if (len > 1) {
			buf = new Sequence[5];
		}
		len = 0;
	}
}